Turnover of phytoplankton and zooplankton communities driven by human-induced disturbances and climate changes in a small urban coastal wetland

Abstract

Urbanization causes immense eutrophication pressure on small urban wetlands, which play a vital role in urban ecosystems. However, our comprehension of the prolonged impacts of eutrophication on these types of wetlands continues to be significantly limited. To address this knowledge gap, we analyzed monthly physical–chemical variables and seasonal phytoplankton and zooplankton communities at the Taipa-Coloane wetland in Macau, China, from 2013 to 2019. Through the generalized additive model (GAM) and principal component analysis (PCA), we found that the aquatic system mainly exhibited interannual variations instead of seasonal variations, with nutrient loads and river discharge (turbidity and salinity) being the most prominent features affected by anthropogenic activities and climate change. Over the years, the increasing turbidity and phytoplankton showed that bottom-up effects predominated the aquatic systems. Under the bottom-up effects of eutrophication and turbidity, the phytoplankton communities showed high adaptation that MP and S1 occupied more dominance after 2016, with higher abundance but lower diversity. Moreover, the bottom-up effects further affected the structure of zooplankton communities. The dominance of rotifers filter feeders (RF) decreased over the years while middle copepods and cladocerans filter feeders (MCF) increased, implying a trend of zooplankton toward large size over time. Overall, our result reveals the bottom-up control pattern in the aquatic systems of small urban wetlands. This research provides valuable insights into the dynamics and responses of plankton communities to environmental changes in small urban wetlands, providing valuable information for future conservation efforts.